Questions tagged [integer]
For challenges involving the manipulation of integers.
11
votes
11answers
1k views
Codegolf Rainbow : Fun with Integer-Arrays
Introduction:
(Source: Wikipedia)
When we look at a rainbow it will always have the colors from top to bottom:
Red; orange; yellow; green; blue; indigo; violet
If we look at these individual rings, ...
15
votes
21answers
1k views
Fill up to duplicate ranges
Let \$L\$ be a list of positive integers with no particular ordering, and which can contain duplicates. Write a program or function which outputs a list of positive integers \$M\$ (whose ordering is ...
25
votes
15answers
2k views
Toggle some bits and get a square
Given an integer \$N>3\$, you have to find the minimum number of bits that need to be inverted in \$N\$ to turn it into a square number. You are only allowed to invert bits below the most ...
17
votes
34answers
905 views
Calculate power series result [duplicate]
Related: Calculate Power Series Coefficients
Given a positive integer \$X\$ and a max exponent (Also a positive integer too) \$N\$ calculate the result of a power series. Example:
$$X^0+X^1+X^2+\...
18
votes
8answers
699 views
Spiral neighbourhoods
If we take the natural numbers and roll them up counter clock-wise into a spiral we end up with the following infinite spiral:
...
13
votes
12answers
2k views
Small Ramsey Numbers
Background: the Ramsey number \$R(r,s)\$ gives the minimum number of vertices \$v\$ in the complete graph \$K_v\$ such that a red/blue edge coloring of \$K_v\$ has at least one red \$K_r\$ or one blue ...
17
votes
7answers
604 views
Stacked digit staircases
Given positive integers \$w\$ and \$h\$ output \$w\$ columns and \$h\$ rows of text as described below.
The first row begins with 11 0s, the second row with 10 <...
-1
votes
7answers
373 views
Calculate the sum of all odd digits of pi in range [duplicate]
Introduction
In the not so distant future with the AI revolution, we will need a way to solve their captchas to prove we're not humans.
This challenge was inspired by CommitStrip.
Challenge
One ...
7
votes
10answers
511 views
How many bytes is it
This time, we want render the count of bytes in a human readable way to user. Let's write a program (a full one or a function or other acceptable formats) to do this.
Input
An non-negative integer, ...
25
votes
30answers
2k views
Let's design a digit mosaic
Challenge
Given a positive integer \$N\$, repeat each of its digits \$d_1, d_2, d_3, \cdots, d_n\$ a number of times corresponding to its position in \$N\$. In other words, each digit \$d_k\$ should ...
21
votes
28answers
2k views
Replace me by the sum of my cyclic successors!
I have a simple challenge for you this time. Given an array of positive integers A (or the equivalent in your language), replace each entry Ai with the sum of the next Ai elements of A, cycling back ...
16
votes
8answers
539 views
Classify a region by its slope
Definitions
The kth ring of a square matrix of size N, where 1 ≤ k ≤ ceiling(N/2) is the list formed by the elements of the kth and (N-k+1)th rows and columns, but without the first and last k-1 ...
21
votes
39answers
3k views
33
votes
42answers
3k views
Up and down, up and down
Challenge:
Given a positive integer input n, create a vector that follows this pattern:
0 1 0 -1 -2 -1 0 1 2 3 2 1 0 -1 -2 -3 -4 -3 -2 -1 ... ±(n-1) ±n
...
3
votes
0answers
155 views
Make Three from One [duplicate]
Given a single digit integer and a three digit integer, output a mathematical formula that uses only the single digit and a given list of operators to equal the three digit integer.
Input: A one ...
24
votes
10answers
2k views
Knight Distance
In Chess, a Knight on grid (x, y) may move to (x-2, y-1), (x-2, y+1), (x-1, y-2), (x-1, y+2), (x+1, y-2), (x+1, y+2), (x+2, y-1), (x+2, y+1) in one step. Imagine an infinite chessboard with only a ...
3
votes
2answers
67 views
Generate lowest degree polynomial from sequence [duplicate]
Introduction
A sequence of numbers is passed in as the input. The program has to generate the lowest degree polynomial possible. This was my first programming project in college and it would be ...
13
votes
13answers
1k views
12
votes
8answers
745 views
Digit Occurrences
Input:
A list of integers (which will never contain a zero)
Output:
A list of the same size with counts based on the following:
If the current item is negative: Look at all items before this item, ...
21
votes
16answers
1k views
Interval Notations
Challenge:
Input:
Two integer parameters a and b (where a<b and the difference is at ...
23
votes
15answers
2k views
Not Quite Roman Ternary
Given an integer n ≥ 0 , output it in a non-positional base-3 notation, using digits 139ABCDE… and a 1-character separator. Every digit is a consecutive power of 3 ...
31
votes
33answers
2k views
Digits in their lanes
Input:
A list of integers
Output:
Put each digit (and the minus sign) in its own lane, in the order -0123456789, ignoring any duplicated digits.
Example:
Input:...
30
votes
47answers
4k views
Which Card is it?
Introduction
Long ago, when I used to code card games with usual playing cards, I used to specify a number for each card and call a function with some number to get a card. This somewhat inspired me ...
20
votes
14answers
1k views
Is this a truncated triangular number?
Related OEIS sequence: A008867
Truncated triangular number
A common property of triangular numbers is that they can be arranged in a triangle. For instance, take 21 and arrange into a triangle of <...
11
votes
3answers
809 views
Crazy but Rational Bases
We have many challenges based on base 10, base 2, base 36, or even base -10, but what about all the other rational bases?
Task
Given an integer in base 10 and a rational base, return the integer in ...
12
votes
5answers
172 views
Reduced Factorization Leader Changes
tl;dr: Output the values where the reduced prime factorization leader changes.
Every positive integer has a unique prime factorization. Let's call the reduced prime factorization just the list of ...
15
votes
19answers
1k views
Make Zero From First 'n' Numbers
Challenge
The challenge is to write a code that takes a positive integer 'n' as an input and displays all the possible ways in which the numbers from 1 - n can be written, with either positive or ...
14
votes
9answers
1k views
Find The Local Maxima And Minima
Definition
The maxima and minima of a given function are the largest and smallest values of the function either within a given range or otherwise within the entire domain of the function.
Challenge
...
32
votes
8answers
762 views
Can square tree rings be generated from primes?
Apparently yes! In three easy steps.
Step 1
Let f(n) denote the prime-counting function (number of primes less than or equal to n).
Define the integer sequence s(n) as follows. For each positive ...
28
votes
8answers
2k views
Find number of ones to get a number using + and *
Introduction
Your goal is to find the least number of ones you need to add or multiply together to get the input value.
Input
One positive integer N.
Output
The smallest number of ones that must ...
14
votes
4answers
869 views
Bottom part of the Hourglass
Challenge:
Input: Three integers: bottom-edge length; starting amount of grains of sand; index
Output: Output the state of the bottom part of an hourglass at the given index, based on the given ...
19
votes
17answers
2k views
Find Integral Roots of A Polynomial
Challenge
The challenge is to write a program that takes the coefficients of any n-degree polynomial equation as input and returns the integral values of x for which the equation holds true. The ...
18
votes
12answers
2k views
Olympic Rings Sequence
Challenge:
Given an index integer n, either output the n'th item in this sequence, or output the sequence up to and including ...
24
votes
61answers
3k views
The Non-Zero Digital Product Challenge
Originally the Multiplicative digital root
Challenge
Basically do what the title says
Method
Given a positive integer 1 <= N <= 100000000 through one of our standard input methods, multiply ...
12
votes
14answers
977 views
Minimise the count of prime factors through insertion
Given two positive integers A and B, return the position p that minimises the number of prime factors (counting multiplicities) of the resulting integer, when B is inserted in A at p.
For example, ...
16
votes
32answers
2k views
Find the largest number of distinct integers that sum to n
The Task
Given an input positive integer n (from 1 to your language's limit, inclusively), return or output the maximum number of distinct positive integers that ...
26
votes
18answers
2k views
Am I a 'Redivosite' Number?
Redivosite is a portmanteau word invented for the sole purpose of this challenge. It's a mix of Reduction, Division and Composite.
Definition
Given an integer N > 6:
If N is prime, N is not a ...
13
votes
20answers
1k views
Compute the Optimal Square Matrix
The optimal matrix (for the rather narrow scope of this challenge) is obtained by "zipping" the elements from the corresponding rows and columns of a square matrix and getting the maximum of each pair....
11
votes
4answers
317 views
Balanced ternary logic
Balanced ternary logic
Ternary is normally another name for base 3, that is to say, each digit is 0, 1, or ...
19
votes
23answers
2k views
Single swaps of an array
Inspired by Taken from a question at Stack Overflow.
The challenge
Given an integer n>1, output all arrays that can be obtained by swapping exactly two entries ...
26
votes
35answers
2k views
Output the hours at 90 degrees
Today while playing with my kids I noticed that an apparently simple toy in the park hid a challenge.
The wheel has a triangle that points to a number, but also has three circles that point to the ...
42
votes
16answers
4k views
How small can it get?
Starting with a positive integer N, find the smallest integer N' which can be computed by repeatedly dividing N by one of its digits (in base-10). Each selected digit must be a divisor of N greater ...
10
votes
6answers
328 views
Is it a Satisfying Number?
inspired by this chat conversation
A satisfying number is a number whose decimal representation is of the form abx, with the following properties:
...
14
votes
11answers
547 views
N-bit Variation on Subset-Sum
For another challenge I am writing, I need to verify that test cases are solveable with bounded integers. Specifically, I need to verify the following, for a non-empty array of integers ...
23
votes
22answers
2k views
Frequency Distribution of Mixed Dice Rolls
A follow-up to this challenge
Given a set of mixed dice, output the frequency distribution of rolling all of them and summing the rolled numbers on each die.
For example, consider ...
23
votes
11answers
1k views
The sequence of self-contained numbers
Let's define a self-contained number as a positive integer, whose digits appear in runs of length equal to themselves only. In other words, any decimal digit d (excluding 0) occurs only in runs of ...
24
votes
25answers
2k views
Find a Fixed Point
Given an integer x1 and some black box function f: ℤ → ℤ find a fixed point of f in the ...
14
votes
31answers
1k views
2 factors factorization
Given a natural number n write a program or function to get a list of all the possible two factors multiplications that can be used to achieve ...
33
votes
30answers
6k views
Find the smallest positive integer which ends in n, is divisible by n and whose digits sum to n
It's all in the title...
Take as input a positive integer n>=12 and... do what the title says.
Yes, this is on OEIS A187924.
Some test cases
...
20
votes
10answers
1k views
Minimal sparse rulers
A standard ruler of length n has distance marks at positions 0, 1, ..., n (in whichever units). A sparse ruler has a subset of those marks. A ruler can measure the distance k if it has marks at ...
